Circuit interrupting devices, such as ground fault circuit interrupters (“GFCIs”) and arc fault circuit interrupters (“AFCIs”) have been widely used by consumers since the 1970s. Nowadays, due to household safety concerns, there are needs for GFCIs with extra safety features. According to new UL standards under UL 943, which are scheduled to be in effect starting in July 2006, a GFCI will be required not only to have reverse wiring protection, but also to be able to provide a user with indications to alert the user when the GFCI has reached the end of its service life and is no longer capable of providing ground fault protection. That is because for most of the GFCIs currently available on the market, when their service life ends, resetting by pressing the reset button is still possible, which gives the users a false sense of security that they are still under proper protection of the GFCI, while in fact the GFCI's capability of sensing a ground fault and interrupting the flow of electricity due to a ground fault may have been compromised. Thus, when a ground fault occurs, the GFCI may be unable to provide any protection, which can result in fatal electric shocks.
In the invention to be presented in the following sections, a newly-designed GFCI which is capable of performing an end of life test is provided. The GFCI of the present invention allows the user to automatically detect whether the service life of the device has ended without operating any parts when a source of electricity has been connected. If the GFCI can be reset, the GFCI shows a continuing capability of detecting a ground fault. If the GFCI cannot be reset, it means that the end of the service life of the GFCI has been reached, and that the user should consider replacing the GFCI.